1. Technical Field
The present invention relates generally to mobile devices, and in particular to systems, methods, and software for handling secure messaging on a wireless communication device.
2. Description of the Related Art
Electronic messages, such as e-mail messages, are typically transmitted from sender to recipient devices in the clear and without verification. It is possible to provide a measure of digital security by either encrypting a message, or by attaching a digital signature to the message, or both. For example, the S/MIME (Secure Multipurpose Internet Mail Extensions) specification, RFC 1847 and associated specifications, published by the Internet Engineering Task Force (http://www.ietf.org/rfc/rfc1847.txt), provide specifications for the secure transmission of MIME-encoded e-mail. However, if the body part of a message is modified after signature, then a recipient will not be able to validate the signature. Further, once a message is to be delivered in encrypted form, its content cannot be altered without decrypting and re-encrypting the message. Alteration of a digitally signed or encrypted message, then, compromises the security of the message.
When a wireless device is used to send and receive messages, it is sometimes desirable to introduce efficiencies into the wireless messaging process to reduce bandwidth and costs. For example, when a new message is sent from a mobile device in reply to a received message, or when a new message is sent from a mobile device forwarding a previously received message, the mobile device and its associated messaging server may operate such that the mobile device only transmits the new content of the new message to the messaging server, and the messaging server then appends the previously received message, which itself is stored at or in association with the messaging server, before causing the complete message to be transmitted to the ultimate recipient.
There has been hitherto an unrecognized need to balance the efficiencies of against the need for security protection. It is therefore desirable to provide an improved system and method for encrypted message handling with a mobile device.